Tone cabinets



June 25, 1963 J. H. HEARNE 3,0 5,059

TONE CABINETS Filed Jan. 3, 1961 2 Sheets-Sheet 1 June 25, 1963 J. H. HEARNE 3, 9

TONE CABINETS Filed Jan. 3, 1961 2 Sheets-Sheet 2 IN VEN TOR.

United States Patent 3,095,059 TONE CABINETS Joseph H. Hearne, Corinth, Miss, assignor to The Wurlitzer Company, Chicago, 111., a corporation of Ohio Filed Jan. 3, 1961, Ser. No. 80,258 12 Claims. (\Cl. Isl-31) This invention relates generally to tone cabinets and especially to tone cabinets arranged to impart vibrato to produced sounds.

In one specific aspect, the present invention relates to tone cabinets for imparting vibrato to the sounds generated by an electronic organ although the invention is not limited to such use.

The sounds or notes produced by an electronic organ, unless modified to impart vibrato, are uninteresting to most listeners. Accordingly, various schemes have been devised for enriching with vibrato the sounds or notes generated by a electronic organ. Electronic means have been developed for periodically altering the pitch and/ or amplitude of the tones. However, these means ordinarily fail to take into consideration the third important aspect of vibrato, namely the periodic variation of that complex tonal attribute generally referred to as timbre. Strictly electronically produced vibrato is therefore inclined to be somewhat shallow.

Mechanical mean-s employing the principles of acousties have also been developed for imparting vibrato to produced sounds. These mechanical means include such devices as revolving horns and rotating vanes. However, these prior art devices do not produce satisfactory variations in timbre; and hence, the vibrato which has heretofore been produced acoustically, like the electronically produced vibrato, is inclined to be shallow because of the lack of appreciable variations in timbre.

Therefore, a general object of the present invention is to provide new and improved means for imparting vibrato to produced sounds.

Another object of the invention is to provide means for imparting a vibrato rich in timbre variations.

Yet another object of the invention is to provide means for incurring variations in all three components of vibrato, namely frequency, amplitude and timbre.

A further object of the invention is to provide means for incurring more rapid vibrato in the higher frequency sounds than in the lower frequency sounds.

Additional objects and features of the invention pertain to the particular structure arrangements whereby the above objects are attained.

A structure in accord with the invention includes means defining a resonant air column including a pipe having apertures spaced apart along the effective length of the air column; means generating sound for driving the column; and stop means for the column including closure rneans for each of the apertures, each of the closure means being movable in a cycle for variously obstructing the corresponding aperture, each of the closure means being further related to the other closure means in fixed, acoustic phase, cyclical operation of the closure means continuously varying the elfective length of the resonant column for producing vibrato eifects.

In order that the principles of the invention may be readily understood, a single embodiment thereof applied to an electronic organ, but to which the application is not to be restricted, is shown in the accompanying drawings wherein:

FIG. 1 is a perspective view of a tone cabinet constructed in accordance with the invention;

FIG. 2. is a side elevational view of the tone cabinet of FIG. 1, partially broken away to reveal interior details;

3,095,059 Patented June 25, 1963 FIG. 3 is a fragmentary, vertical cross-sectional view of the tone cabinet of FIG. 1;

FIG. 4 is a front elevational view of the tone cabinet of FIG. 1 showing the 01051.116 means in one position;

FIG. 5 is a view similar to the showing of FIG. 4 but illustrating the closure means in a different position;

FIG. 6 is a View similar to the showing of FIG. 2, particularly illustrating the drive means being re-arranged for reverse rotation of the closure means; and

FIG. 7 is a perspective View of the closure means coupled to form a rotor assembly.

Referring now in detail to the drawings, specifically to FIG. 1, a tone cabinet indicated generally by the numeral It; will be seen to include a horizontal platform 12. A bass register loudspeaker or electroacoustic transducer 14 is mounted on platform 12 with its output end opening in a generally downward direction through a hole fashioned in the platform. A backsloading enclosure or bafile 16 is mounted in super position to the platform 12 surrounding the loudspeaker l4. Baffle 16 and loudspeaker 14 may comprise either a bass reflex or an acoustic suspension arrangement.

The loudspeaker 14 is arranged to receive signals from an electronic organ, not shown; and in accordance with conventional practice, the output of the electronic organ is split in mid-range by a dividing network, the lower frequencies being conducted to the loudspeaker 14 and the higher frequencies being conducted to a treble register loudspeaker or electroacoustic transducer 1%. The signals which are conducted to the loudspeaker 14 and to the loudspeaker 1-8 respectively are desirably provided with a degree of overlap or common frequency range, as is well known. Loudspeaker 18 is advanta geously mounted to baffle 16 in the position illustrated.

Platform 12 defines the top of a front battle or enclosure 20, enclosure as also including side walls 22, back wall 24 and an open side 26. A floor 28 is additionally provided, and a partition so is provided clos ing off the lower portion of open side 26. Since enclosure 20 is intended to form a pipe resonator a vertical partition 32 is mounted within the enclosure to bisect the enclosure along a central axis perpendicular to the open side 26. As is shown in FIG. 2, partition 32 extends into contact with partition 30 but terminates short of the floor 28. Thus, the pipe resonator defined by enclosure 29 is fashioned with one end folded back. A crosspiece or transom strip 34 is advantageously fixed across open side 26 adjacent the platform 12.

In accord with the invention, closure means are provided for the two apertures 36', 38' defined on the opposite sides of partition 32 in the open side 26 of enclosure 20; and these closure means specifically comprise a pair of panels or vanes 36 and 38. The vanes 36 and 38 are combined in a rotor assembly by having pivot pins 46) fixed extending outwardly from the edges of the panels aligned with a central axis thereof, the panels being disposed at right angles to each other at this axis, as is generally indicated in the several figures. Furthermore, journal brackets 42 are atfixed to the side walls 22 and to the partition 32 for receiving the pins 40 and rotatably mounting the panels 36 and 38 with respect to the open side 26 of enclosure 26. Panels 36 and 38 are spaced apart along the rotational axis so as to avoid colliding with partition 32.

In order to cycle the closure means through various aperture-obstructing positions, drive means are provided including an electric motor 44, a small diameter pulley 46 fixed to the output shaft of motor 44, a large diameter pulley 48 fixed to a pivot pin 46*, and a flexible drive.

belt 50 connecting the pulleys 46 and 48. Motor 44 is advantageously mounted to the upper surface of platform 12 adjacent bafile 16; and under certain circumstances,

3 it has proved desirable to protect the pulleys and drive belt with a shroud, not shown. Moreover, it is within the comprehension of the invention to substitute a single shaft for the several pivot pins 4t Motor 44 is advantageously arranged to provide a constant speed drive.

Being intended to act as a pipe resonator, enclosure 26' is desirably fabricated from hard, sound-reflective materials, for example highly polished hardwoods, the interior surfaces of the enclosure, the fioor 2.8 and the surfaces of vanes 3e and 38 being particularly critical in this regard. In addition, the dimensions of enclosure 2%, especially insofar as they determine the effective length of the resonant air column, are selected to accommodate the lowest frequencies which are intended to be reproduced, the path length being a function of the wave length of the sound, as is well known.

For purposes of affording a more complete understanding of the invention and in order to point out the significance of the desired arrangements, it is advantageous now to provide a functional description of the mode in which the component parts cooperate.

The closure means defined by vanes 36 and 38 are arranged to take two extreme positions, and these two extreme positions are shown respectively in FIGS. 4 and 5. In FIG. 4, the vane 36 is shown completely unblocking its respective aperture whereas vane 33 is in completely obstructing position. FIG. 4 illustrates the maximum effective length of the resonant air column wherein sound waves emanating from loudspeaker 14- are directed downwardly between back wall 24- and vane 38 and across the floor 28 to emerge on either side of vane 36.

With particular reference to FIG. 2, it will be observed that, in its aperture-unblocking condition, vane 36 terminates at a point substantially spaced apart from the back wall 24. Thereby, some part of the radiations from loudspeaker 1d are passed out of enclosure 20 from a position above the vane 36 although the bulk of the radiations emanate from beneath the vane 36 as is generally indicated in FIG. 2 by the arrows 52. This arrangement of the length of vane 36 is likewise followed for vane 38.

By permitting some of the sound waves to emerge from a position above the vane 36 while the bulk emerges from a position below the vane 36, a certain amount of time-spacing of the signals is achieved, a slightly reduced frequency being experienced by those radiations emanating from above the vane 36 due to the extension of the traveled path. The average effect of this arrangement is a harmonic enrichment or alteration of the wave form which is eventually received by a listener.

FIG. 5 illustrates the second extreme position of the closure means; and there, vane 36 will be seen completely closing off its respective aperture whereas vane 38 is in unblocking condition. This represents the minimum length resonant air column; and like the maximum column length conditon, radiations emanating from the loudspeaker 14 are permitted to emerge from both beneath and above the vane 38 whereby to provide harmonic enrichment.

Moreover, when the vanes are positioned as illustrated in FIG. 5, vane 38 is partially exposed to direct radiation from the loudspeaker :14; and since the vanes are in continuous motion, the waves reflected from the surface of vane 38 variously reinforce and cancel the output of the loudspeaker 14. Thus, there is achieved an alteration in the amplitude of the output from the tone cabinet as vane 38 moves relative to the loudspeaker 14. In this regard, it is important to note that the provision of a sound path between the back wall 24- and the inwardly extending edge of vane 38 prevents the amplitude variations from passing through a zero condition, i.e. the output wave of loudspeaker 14 is, in effect, modulated by the variations in the amplitude signal.

It will become apparent that, as the vanes 36 and 38 are rotated and continuously move from one extreme position to the other, the resonant frequency of the air column which is defined by enclosure 2b is in a state of continual variation. When the pipe takes its longest efiective length, the lower frequency radiations and the lower harmonics from loudspeaker 14 are reinforced whereas the higher frequencies and higher harmonics are not appreciably reinforced. When the pipe takes its shortest effective length, the higher frequency radiations and the higher harmonics are benefitted by the reinforcement. Hence, the continuous alteration of the effective length of the resonant air column tends to alter the harmonic enrichment of the over all output, thereby providing the variations in wave form which are necessary to achieve variations in timbre. A full-bodied vibrato results.

Similarly, as the length of the path which the radiations from loudspeaker 1d traverse varies from the two extreme positions, a phase shift is evident because of the time consumed while the wave is travelling the length of the pipe. There results a pitch or frequency variation.

Thus, the vibrato effects imparted to the output radiations from loudspeaker 14 comprise variations in timbre as well as variations in amplitude and frequency.

It is to be noted that a complete cycle, i.e. a change from one extreme position to the other and back to the starting condition, is achieved by rotating the closure means through an arc of Since the normal vibrato rate is seven cycles per second, it is therefore advantageous to drive the rotor assembly at a speed of approximately 3.5 revolutions per second. Moreover, a close fit between the respective vanes and the surrounding aperturedefining members has been found to produce sharper effects.

Ideally, the vibrato rate is increased for the higher frequencies; and the present invention makes provision for doubling the vibrato rate for the higher frequencies as compared with the vibrato rate for the lower frequencies. Specifically, the treble register loudspeaker 18 is situated in alignment with the confronting edges of vanes 36 and 38 as is well shown in FIGS. 4 and 5, the loudspeaker 18 being located outside of the resonant air column defined by enclosure 20, as is illustrated. By means of this arrangement, the vanes 36 and 38 are exposed to the direct radiations 53, shown in FIGS. 2 and 3, from loudspeaker 18. Reflection from the moving vanes affords variations in amplitude and also variations in frequency due to a Doppler effect. Since the radiations from loudspeaker 18 are directed at both of the vanes, the effective vibrato rate for the higher frequency radiations is substantially double the vibrato rate for the lower frequency radiations from loudspeaker 14.

A further modification in the character of the vibrato can be achieved by reversing the direction in which the closure means are rotated. In FIGS. 1 thru 5, the rotor assembly is arranged to be driven in the direction indicated by arrow 54 in FIG. 3 whereas, in FIG. 6, the rotor assembly is arranged to be driven in the direction indicated by arrow 56. This alteration in the direction of rotation is achieved by crossing the belt 50, as is shown in FIG. 6, or by other suitable means.

The present invention finds its principal utility in conjunction with electronic organics although it has other desirable uses, such as for example in providing novel effects to a recorded voice. Therefore, the specific example herein shown and described should be considered as illustrative only. Various changes in structure may occur to those skilled in the art; and these changes are to be understood as forming a part of this invention insofar as they fall within the spirit in scope of the appended claims.

The invention is claimed as follows:

1. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having a plurality of generally radially opening apertures spaced apart along the effective length of said column intermediate the ends thereof; sound generating means disposed at one end of said column and operatively connected thereto for driving said column and operatively connected thereto for driving said column; and stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being movable in a cycle for variously obstructing the corresponding aperture.

2. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having a plurality of generally radially opening apertures spaced apart along the effective length of said column intermediate the ends thereof; sound generating means disposed at one end of said column and operatively connected thereto for driving said column; and stop means connected to said columndefinin-g means, including closure means for each of said apertures, each of said closure means being related to the other closure means in fixed phase, cyclical operation of said closure means continuously varying the effective length of said resonant column for producing vibrato effects.

3. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having at least one end folded back, said pipe having a plurality of generally radially opening apertures spaced apart along the eifective length of said column intermediate the ends thereof and disposed physically adjacent to each other; sound generating means disposed at one end of said column and operatively connected thereto for driving said column; stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being moveable in a cycle for variously obstructing the corresponding aperture, said stop means comprising a rotor assembly having a rotatable, axis-defining means and a plurality of flat vanes centrally fixed to said axis-defining means, said vanes being disposed perpendicular to each other at said axis-defining means, each of said vanes defining a said closure member; and drive means mechanically coupled to said axis-defining means operable to rotate said closure means in a selected direction, cyclical operation of said closure means continuously varying the effective length of said resonant column for producing vibrato effects.

4. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having a plurality of generally radially opening apertures spaced apart along the effective length of said column intermediate the ends thereof; sound generating means disposed at one end of said column and operatively connected thereto for driving said columns; and stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being movea'ble in a cycle for variously obstructing the corresponding aperture, each of said closure means being related to the other closure means in a fixed, acoustic phase of 180, cyclical operation of said closure mean-s continuously varying the effective length of said resonant column for producing vibrato effects.

5. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having a plurality of generally radial opening apertures spaced apart along the eifective length of said column intermediate the ends thereof; bass register sound generating means disposed at one end of said column and operatively connected thereto for driving said column; stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being moveable in a cycle partly within and partly outside said column for variously obstructing the corresponding aperture; and treble register sound generating means fixed with respect to said column-defining means external to said column and focused into the path of movement of said closure means outside said column, cyclical operation of said closure means continuously varying the effective length of said resonant column and continuously varying the coupling of said treble register sound to the air for producing vibrato effects.

6. Apparatus according to claim 5 wherein said means generating sound in the bass register include bass loudspeaker and a baflle enclosure.

7. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having at least one end folded back, said pipe having a plurality of generally radial opening apertures spaced apart along the effective length of said column intermediate the ends thereof and disposed physically adjacent to each other; bass register sound generating means disposed at one end of said column and operatively connected thereto for driving said column; stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being moveable in a cycle partly within and partly outside said column for variously obstructing the corresponding aperture, each of said closure means being related to the other closure means in fixed, acoustic phase; and treble register sound generating means fixed with respect to said column-defining means and focused into the path of movement of said closure means to impinge the treble register sound Waves on generally adjacently disposed edge portions of said closure means, cyclical operation of said closure means continuously varying the effective length of said resonant column and continuously varying the coupling of said treble register sound to the air for producing vibrato effects.

8. Apparatus for modifying the character of sound waves, said apparatus comprising: means defining a resonant air column including a pipe having a plurality of generally radially opening apertures spaced apart along the effective length of said column intermediate the ends thereof and disposed physically adjacent to each other; means generating sound in one register, said last mentioned means being disposed at one end of said column operatively connected thereto for driving said column; stop means connected to said column-defining means, including closure means for each of said apertures, each of said closure means being moveable in a cycle partly within and partly outside said column for variously obstructing the corresponding aperture, each of said closure means being related to the other closure means in fixed, acoustic phase; means generating sound in another reg ister, said last mentioned means being operatively connected to said column-defining means external to said pipe and focused into the path of said closure means outside of the confines of said column; and drive means mechanically coupled to said closure means and operable to rotate said closure means in a selected direction, cyclical operation of said closure means continuously varying the effective length of said resonant column and continuously varying the coupling of the sound in said other register for producing vibrato effects.

9. A tone cabinet comprising: a loudspeaker; a back baffle enclosure connected to the rear portion of said loudspeaker in housing relationship therewith; a front bafile enclosure connected to said loudspeaker and open to the sound waves emanating therefrom, the axis of said loudspeaker being disposed parallel to and spaced apart from a central axis of said front bafile enclosure, said front baifie enclosure having an open side adjacent the output end of said loudspeaker; a first partition closing off a portion of said open side opposite said loudspeaker; a second partition bisecting said front baffle enclosure along said central axis perpendicular to said open side, said second partition extending into contact with said first partition and terminating short of the end of said front bafile enclosure opposite said loudspeaker; a first panel rotatably mounted selectively to close said open side on one side of said second partition; a second panel 7 rotatably mounted selectively to close ofi said open side on the other side of said second partition; and drive means mechanically coupled to said first and second panels for rotating said panels about a common axis.

10. A tone cabinet according to claim 9 wherein the radial length of said panels is less than the depth of said front bafile enclosure.

11. A tone cabinet comprising: a loudspeaker; a back bafile enclosure connected to the rear portion of said loudspeaker in housing relationship therewith; a front battle enclosure connected to said loudspeaker and open to the sound waves emanating therefrom, the axis of said loudspeaker being disposed parallel to and spaced apart from a central axis of said front baffle enclosure, said front bafile enclosure having an open side adjacent to the output end of said loudspeaker; a first partition closing off a portion of said open side opposite said loudspeaker; a second partition bisecting said front baffie enclosure along said central axis perpendicular to said open side, said second partition extending into contact with said first partition and terminating short of the end of said front baffie enclosure opposite said loudspeaker; a first panel rotatably mounted selectively to close off said open side on one side of said second partition; a second panel rotatably mounted selectively to close off said open side on the other side of said second partition, said panels further being disposed at right angles to each other; and drive means mechanically coupled to said first and second panels for rotating said panels about a common axis.

12. A tone cabinet comprising: a bass loudspeaker;

:1 back bafile enclosure connected to the rear portion of said loudspeaker in housing relationship therewith; a front bafiie enclosure connected to said loudspeaker and open to the sound waves emanating therefrom, the axis of said loudspeaker being disposed parallel to and spaced apart from a central axis of said front bafiie enclosure, said front bafile enclosure having an open side adjacent to the output end of said loudspeaker; a first partition closing off a portion of said open side opposite said loudspeaker; a second partition bisecting said front baffie enclosure along said central axis perpendicular to said open side, said second partition extending into contact with said first partition and terminating short of the end of said front baffle enclosure opposite said loudspeaker; a first panel rotatably mounted selectively to close said open side on one side of said second partition; a second panel rotatably mounted adjacent said first panel selectively to close off said open side on the other side of said second partition; drive means mechanically coupled to said first and second panels for rotating said panels about a common axis; and a high-frequency loudspeaker fixed with respect to said front baifie enclosure, the output end of said high-frequency loudspeaker opening toward adjacent edges of said panels.

References Cited in the file of this patent UNITED STATES PATENTS 

1. APPARATUS FOR MODIFYING THE CHARACTER OF SOUND WAVES, SAID APPARATUS COMPRISING: MEANS DEFINING A RESONANT AIR COLUMN INCLUDING A PIPE HAVING A PLURALITY OF GENERALLY RADIALLY OPENING APERTURES SPACED APART ALONG THE EFFECTIVE LENGTH OF SAID COLUMN INTERMEDIATE THE ENDS THEREOF; SOUND GENERATING MEANS DISPOSED AT ONE END OF SAID COLUMN AND OPERATIVELY CONNECTED THERETO FOR DRIVING SAID COLUMN AND OPERATIVELY CONNECTED THERETO FOR DRIVING SAID COLUMN; AND STOP MEANS CONNECTED TO SAID COLUMN-DEFINING MEANS, INCLUDING CLOSURE MEANS FOR EACH OF SAID APERTURES, EACH OF SAID CLOSURE MEANS BEING MOVABLE IN A CYCLE FOR VARIOUSLY OBSTRUCTING THE CORRESPONDING APERTURE. 